Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758559AbZAGO5B (ORCPT ); Wed, 7 Jan 2009 09:57:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754046AbZAGO4s (ORCPT ); Wed, 7 Jan 2009 09:56:48 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:51749 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752798AbZAGO4r (ORCPT ); Wed, 7 Jan 2009 09:56:47 -0500 Date: Wed, 7 Jan 2009 15:56:21 +0100 From: Ingo Molnar To: Matthew Wilcox Cc: Chris Mason , Nick Piggin , Peter Zijlstra , Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel , linux-btrfs , Thomas Gleixner , Steven Rostedt , Gregory Haskins Subject: Re: Btrfs for mainline Message-ID: <20090107145621.GB23455@elte.hu> References: <1230722935.4680.5.camel@think.oraclecorp.com> <1231093310.27690.5.camel@twins> <20090104184103.GE2002@parisc-linux.org> <200901060147.24285.nickpiggin@yahoo.com.au> <1231173015.4290.129.camel@think.oraclecorp.com> <20090107130742.GD3529@elte.hu> <20090107132447.GR2002@parisc-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090107132447.GR2002@parisc-linux.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 36 * Matthew Wilcox wrote: > On Wed, Jan 07, 2009 at 02:07:42PM +0100, Ingo Molnar wrote: > > * Chris Mason wrote: > > > All of this is a long way of saying the btrfs locking scheme is far from > > > perfect. I'll look harder at the loop and ways to get rid of it. > > > > > > > > adaptive spinning mutexes perhaps? Such as: > > Um, I don't know how your mail client does threading, but mine shows > Peter's message introducing the adaptive spinning mutexes as a reply to > one of Chris' messages in the btrfs thread. > > Chris is just saying he'll look at other ways to not need the spinning > mutexes. But those are not the same spinning mutexes. Chris wrote his mail on Jan 05, Peter his first mail about spin-mutexes on Jan 06, as a reaction to Chris's mail. My reply links back the discussion to the original analysis from Chris pointing out that it would be nice to try BTRFS with plain mutexes plus Peter's patch - instead of throwing away BTRFS's locking design or anything intrusive like that. Where's the problem? :) Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/